A reappraisal of activity metabolism in Atlantic cod (Gadus morhua)

Atlantic cod (Gadus morhua) were forced to swim in a swim tunnel respirometer until fatigued; oxygen consumption rate (ṀO2) was measured during swimming at incremental speeds until the fish was exhausted and during recovery from exhaustion. Maximal oxygen consumption (ṀO2max) occurred during maximal activity as has been found for other fish species, but at odds with the current paradigm for Atlantic cod. Earlier experiments had drawn the conclusion that ṀO2max in Atlantic cod occurs during recovery from exhaustive exercise. We found no support for this paradigm in our experiments and we propose that the respiratory physiology of Atlantic cod is not unlike that of other fishes.